The following package installs the com.apple.celestial.plist file and the SystemSoundMaximumVolume.plist files as found at http://limitededitioniphone.com/low-volume-on-your-iphone-steps-to-fix/

I personally do not notice a difference in volume, however I'm already using 1.1.1. Perhaps users of 1.0.2 will benefit. The package will back up your original files during install and restore them during the uninstall.

Best of luck!